More frustration

In reference to last night's session, turning off auto-contrast and setting contrasts to the extremes did not work. The bright/hot pixels still leak through. I was not that careful aligning the polar axis thus the bright/hot pixel trails are still present. One different thing I did try was checking the sharp instead of soft setting in the color dialog. This substantially sharpened the star images but also increases noise and probably lowers sensitivity. See M13 below.

M13

I'm in Maryland but will return to Massachusetts tomorrow. Weather forecast suggests I won't have another opportunity until Wednesday earliest. I'll try to do a much better alignment and image then.

Some frustration

In the United States Northeast I don't get a lot of clear nights out. And, for the few I get transparency ain't that great. Since my early successes with the DSI things have not gone well. I get the camera temperature stabilized, collect dark frames and start imaging. Here's the problem. Dark frame subtraction seems never to get rid of the big permanent pixels. This manifests itself as colored streaks such as those in the image of M-13 below.

This had not been a problem with the DSI when I first started using it. I wondered if scope alignment was the big issue. I don't have a permanent location. When in Massachusetts I take the scope to a local park, set up and align, set up the camera and shoot. In Maryland, I use the back yard but have to do an alignment each time. I don't think my aligning is so much better than earlier times to make a difference.

Recently I found this this webpage where the author mentions the contrast control. I hooked up the DSI and it dawned on me that instead of leaving it with auto-contrast checked I should try setting the contrast to 0 and its maximum 65536. With this setting the bright pixels vanish. On my next night out I'll try this setting to see if the problems clear. Fingers crossed.